1. Field of the Invention
The present invention relates to an exposure method and apparatus which draw a pattern on a substrate such as a wafer or glass plate using a charged particle beam such as an electron beam or an ion beam.
2. Description of the Related Art
Electron beam exposure apparatuses are roughly classified into apparatuses for scanning a point beam on a wafer to draw a pattern and apparatuses for shaping an electron beam into a desired shape using a mask and transferring the mask pattern on a wafer. In both apparatuses, to expose a pattern on the entire wafer surface, the stage on which the wafer is placed must be moved to move the wafer relative to the electron beam.
In such a conventional apparatus, however, as the stage moves, the position of the electron beam changes accordingly, and the pattern cannot be drawn or transferred to the desired position on the wafer. This is probably because the electromagnetic field near the electron beam varies during movement of the stage. Especially, when a magnetic material is used for the stage which moves, the position of the electron beam conspicuously changes during movement of the stage.
Particularly, since the position of the electron beam changes during movement of the stage, the imaging characteristics (e.g., the focus position or astigmatic amount) of the electron beam may vary, and the pattern cannot be drawn or transferred to the desired position on the wafer. This is probably because the electromagnetic field near the electron beam varies during movement of the stage. Especially, when a magnetic material is used for the stage which moves, the imaging characteristics (e.g., the focus position or astigmatic amount) of the electron beam conspicuously vary during movement of the stage.
It is the object of the first and second aspects of the present invention to, e.g., suppress degradation in drawing accuracy due to a change in position of a charged particle beam during movement of a stage.
According to the first aspect of the present invention, there is provided an exposure method of placing a substrate on a stage and drawing a pattern on the substrate using a charged particle beam, comprising the correction step of correcting a position where the charged particle beam is incident on the substrate in drawing, in accordance with a position of the stage.
In the exposure method according to the first aspect of the present invention, for example, the correction step preferably comprises controlling a deflector for deflecting the charged particle beam to correct the position where the charged particle beam is incident on the substrate in drawing.
In the exposure method according to the first aspect of the present invention, for example, the correction step preferably comprises controlling the position of the stage to correct the position where the charged particle beam is incident on the substrate in drawing.
In the exposure method according to the first aspect of the present invention, for example, the correction step preferably comprises correcting a shift of the position where the charged particle beam is incident on the substrate, the shift being generated in accordance with the position of the stage.
In the exposure method according to the first aspect of the present invention, for example, the correction step preferably comprises correcting a reference position of the charged particle beam on the substrate in accordance with the position of the stage to correct the position where the charged particle beam is incident on the substrate in drawing.
In the exposure method according to the first aspect of the present invention, for example, the reference position is preferably a position where the charged particle beam is incident on the substrate without being deflected by a deflector.
In the exposure method according to the first aspect of the present invention, preferably, for example, the method further comprises the drawing step of drawing the pattern in each of a plurality of shot regions on the substrate, and the correction step comprises continuously correcting the position where the charged particle beam is incident on the substrate, in accordance with the position of the stage while the pattern is being drawn in each shot region.
In the exposure method according to the first aspect of the present invention, preferably, for example, the method further comprises the drawing step of drawing the pattern in each of a plurality of shot regions on the substrate while moving the stage to switch the shot region where the pattern is to be drawn, and the correction step comprises correcting the position where the charged particle beam is incident on the substrate, in accordance with a position of the shot region where the pattern is to be drawn.
In the exposure method according to the first aspect of the present invention, preferably, for example, the method further comprises the check step of checking a relationship between the position of the stage and the position where the charged particle beam is incident on the substrate, and the correction step comprises correcting the position where the charged particle beam is incident on the substrate in drawing, on the basis of a check result in the check step.
In the exposure method according to the first aspect of the present invention, for example, the check step preferably comprises checking a shift of the position where the charged particle beam is incident on the substrate, the shift being generated in accordance with the position of the stage.
In the exposure method according to the first aspect of the present invention, for example, the check step preferably comprises the placing step of placing a calibration substrate on the stage, the drawing step of drawing a calibration pattern on the calibration substrate, the detection step of detecting a position of the calibration pattern drawn in the drawing step, and the calculation step of calculating the difference between the position of the calibration pattern detected in the detection step and a designed position of the calibration pattern.
In the exposure method according to the first aspect of the present invention, preferably, for example, the drawing step comprises drawing the pattern using, as a target position, a designed reference position of the charged particle beam on the substrate, and the calculation step comprises calculating the difference between an actual reference position as the position of the pattern detected in the detection step and the designed reference position.
In the exposure method according to the first aspect of the present invention, for example, the correction step preferably comprises correcting the position where the charged particle beam is incident on the substrate in drawing such that the actual reference position matches the designed reference position.
In the exposure method according to the first aspect of the present invention, preferably, for example, the calibration substrate placed on the stage in the placing step is coated with a resist, the method further comprises the development step of developing the calibration substrate after the drawing step, and the detection step comprises detecting a position of a pattern formed in the development step.
In the exposure method according to the first aspect of the present invention, for example, the stage contains a magnetic material.
In the exposure method according to the first aspect of the present invention, for example, the stage is supported by static pressure bearings and a preloading mechanism.
In the exposure method according to the first aspect of the present invention, for example, the preloading mechanism comprises a magnetic preloading mechanism, a vacuum preloading mechanism, or an electrostatic preloading mechanism.
In the exposure method according to the first aspect of the present invention, for example, the charged particle beam is an electron beam.
According to the second aspect of the present invention, there is provided an exposure apparatus for drawing a pattern on a substrate using a charged particle beam, comprising a charged particle beam source for generating the charged particle beam, a stage which moves while having the substrate placed on the stage, and a correction section for correcting a position where the charged particle beam is incident on the substrate in drawing, in accordance with a position of the stage.
In the exposure apparatus according to the second aspect of the present invention, preferably, for example, the apparatus further comprises a deflector for deflecting the charged particle beam generated by the charged particle beam source, and the correction section controls the deflector to correct the position where the charged particle beam is incident on the substrate in drawing.
It is the object of the third and fourth aspects of the present invention to, e.g., suppress degradation in drawing accuracy due to a variation in position of a charged particle beam during movement of a stage.
According to the third aspect of the present invention, there is provided an exposure method of drawing a pattern on a substrate using a charged particle beam, comprising the detection step of placing a calibration substrate having a plurality of marks on a stage and detecting positions of the plurality of marks by a first position detection section using a charged particle beam and by a second position detection section using light while adjusting a position of the stage, and the correction step of correcting a position where the charged particle beam is incident on the substrate on which the pattern is to be drawn in drawing, in accordance with the position of the stage on the basis of the difference between detection results by the charged particle beam and the light in the detection step.
In the exposure method according to the third aspect of the present invention, for example, the charged particle beam used in the detection step and the charged particle beam for drawing the pattern on the substrate on which the pattern is to be drawn are preferably generated by the same electron optical system.
In the exposure method according to the third aspect of the present invention, preferably, for example, the method further comprises the determination step of detecting a position of a reference mark formed on the stage by the first position detection section using the charged particle beam and the second position detection section using the light to determine the positional relationship between a reference position of the first position detection section and a reference position of the second position detection section, and the correction step comprises correcting a reference position of the charged particle beam in accordance with the position of the stage on the basis of the difference between the detection results by the charged particle beam and the light in the detection step such that the positional relationship between the reference position of the charged particle beam incident on the substrate on which the pattern is to be drawn in drawing and the reference position of the second position detection section matches the positional relationship between the reference position of the first position detection section and the reference position of the second position detection section.
In the exposure method according to the third aspect of the present invention, for example, the correction step preferably comprises obtaining, on the basis of the position of the stage and the detection result by the charged particle beam and that by the light, the relationship between the position of the stage and a shift of the position where the charged particle beam is incident on the substrate from a target position and correcting the position where the charged particle beam is incident on the substrate on which the pattern is to be drawn in drawing, on the basis of the relationship in accordance with the position of the stage.
In the exposure method according to the third aspect present invention, for example, the correction step preferably comprises controlling a deflector for deflecting the charged particle beam to correct the position where the charged particle beam is incident on the substrate on which the pattern is to be drawn in drawing.
In the exposure method according to the third aspect of the present invention, for example, the correction step preferably comprises controlling the position of the stage to correct the position where the charged particle beam is incident on the substrate on which the pattern is to be drawn in drawing.
In the exposure method according to the third aspect of the present invention, for example, the correction step preferably comprises correcting a shift of the position where the charged particle beam is incident on the substrate on which the pattern is to be drawn, the shift being generated in accordance with the position of the stage.
In the exposure method according to the third aspect of the present invention, for example, the correction step preferably comprises correcting a reference position of the charged particle beam on the substrate in accordance with the position of the stage to correct the position where the charged particle beam is incident on the substrate on which the pattern is to be drawn in drawing.
In the exposure method according to the third aspect of the present invention, for example, the reference position is preferably a position where the charged particle beam is incident on the substrate on which the pattern is to be drawn without being deflected by a deflector.
In the exposure method according to the third aspect of the present invention, preferably, for example, the method further comprises the drawing step of drawing the pattern in each of a plurality of shot regions on the substrate on which the pattern is to be drawn, and the correction step comprises continuously correcting the position where the charged particle beam is incident on the substrate on which the pattern is to be drawn, in accordance with the position of the stage while the pattern is being drawn in each shot region.
In the exposure method according to the third aspect of the present invention, preferably, for example, the method further comprises the drawing step of drawing the pattern in each of a plurality of shot regions on the substrate on which the pattern is to be drawn while moving the stage to switch the shot region where the pattern is to be drawn, and the correction step comprises correcting the position where the charged particle beam is incident on the substrate on which the pattern is to be drawn, in accordance with a position of the shot region where the pattern is to be drawn.
In the exposure method according to the third aspect of the present invention, for example, the stage contains a magnetic material.
In the exposure method according to the third aspect of the present invention, for example, the stage is supported by static pressure bearings and a preloading mechanism.
In the exposure method according to the third aspect of the present invention, for example, the preloading mechanism comprises a magnetic preloading mechanism, a vacuum preloading mechanism, or an electrostatic preloading mechanism.
In the exposure method according to the third aspect of the present invention, for example, the charged particle beam is an electron beam.
According to the fourth aspect of the present invention, there is provided an exposure apparatus for drawing a pattern on a substrate using a charged particle beam, comprising a stage which moves while having the substrate placed on the stage, an electron optical system having a function of drawing the pattern on the substrate using the charged particle beam and a function of irradiating a mark with the charged particle beam and detecting a position of the mark on the basis of the charged particle beam from the mark, an alignment optical system for irradiating a mark with light and detecting a position of the mark on the basis of light from the mark, and a control section, the control section controlling processing including the detection step of, while a calibration substrate having a plurality of marks is placed on the stage, detecting positions of the plurality of marks by the electron optical system and by the alignment optical system while adjusting a position of the stage, and the correction step of correcting a position where the charged particle beam is incident on the substrate on which the pattern is to be drawn in drawing, in accordance with the position of the stage on the basis of the difference between detection results by the charged particle beam and the light in the detection step.
It is the object of the fifth and sixth aspects of the present invention to, e.g., suppress degradation in drawing accuracy due to a variation in position of a charged particle beam during movement of a stage and, more particularly, suppress degradation in drawing accuracy due to a variation in imaging characteristics of a charged particle beam during movement of the stage.
According to the fifth aspect of the present invention, there is provided an exposure method of placing a substrate on a stage and drawing a pattern on the substrate using a charged particle beam, comprising the correction step of correcting imaging characteristics of the charged particle beam in accordance with a position of the stage.
In the exposure method according to the fifth aspect of the present invention, for example, the imaging characteristics of the charged particle beam corrected in the correction step preferably include a focus position.
In the exposure method according to the fifth aspect of the present invention, for example, the imaging characteristics of the charged particle beam corrected in the correction step preferably include an astigmatic amount.
In the exposure method according to the fifth aspect, of the present invention, for example, the correction step preferably comprises adjusting at least one of a dynamic stigmatic coil and a dynamic focus coil to correct the imaging characteristics of the charged particle beam.
In the exposure method according to the fifth aspect of the present invention, preferably, for example, the method further comprises the check step of checking the relationship between the position of the stage and the imaging characteristics of the charged particle beam, and the correction step comprises correcting the imaging characteristics of the charged particle beam in accordance with the position of the stage on the basis of a check result in the check step.
In the exposure method according to the fifth aspect of the present invention, for example, the check step preferably comprises checking the imaging characteristics of the charged particle beam at each of a plurality of positions of the stage while sequentially moving the stage to the plurality of positions.
In the exposure method according to the fifth aspect of the present invention, for example, the check step preferably comprises the steps of placing a calibration substrate having a plurality of marks on the stage, and observing images of the marks while moving the stage in accordance with the positions of the marks to obtain the imaging characteristics of the charged particle beam in accordance with the position of the stage.
In the exposure method according to the fifth aspect of the present invention, for example, the stage contains a magnetic material.
In the exposure method according to the fifth aspect of the present invention, for example, the stage is supported by static pressure bearings and a preloading mechanism.
In the exposure method according to the fifth aspect of the present invention, for example, the preloading mechanism comprises a magnetic preloading mechanism, a vacuum preloading mechanism, or an electrostatic preloading mechanism.
In the exposure method according to the fifth aspect of the present invention, for example, the charged particle beam is an electron beam.
According to the sixth aspect of the present invention, there is provided an exposure apparatus for drawing a pattern on a substrate using a charged p article beam, comprising a charged particle beam source for generating the charged particle beam, a stage which moves while having the substrate placed on the stage, and a correction section for correcting imaging characteristics of the charged particle beam in accordance with a position of the stage.
It is the object of the seventh to ninth aspects of the present invention to prevent degradation in drawing accuracy due to a change in position of a charged particle beam during movement of a stage and to allow manufacture of an accurate device.
According to the seventh aspect of the present invention, there is provided a device manufacturing method comprising the steps of placing a substrate on a stage of a charged particle beam exposure apparatus and drawing a pattern on the substrate using a charged particle beam while correcting a position where the charged particle beam is incident on the substrate, in accordance with a position of the stage, and developing the substrate on which the pattern is drawn.
According to the eighth aspect of the present invention, there is provided a device manufacturing method comprising the steps of placing a calibration substrate having a plurality of marks on a stage and detecting positions of the plurality of marks by a first position detection section using a charged particle beam and a second position detection section using light while adjusting a position of the stage, drawing a pattern on a substrate on which the pattern is to be drawn using a charged particle beam while correcting a position where the charged particle beam is incident on the substrate in drawing, in accordance with a position of the stage on the basis of the difference between detection results by the charged particle beam and the light in the detection step, and developing the substrate on which the pattern is drawn.
According to the ninth aspect of the present invention, there is provided a device manufacturing method comprising the steps of placing a substrate on a stage of a charged particle beam exposure apparatus and drawing a pattern on the substrate while correcting imaging characteristics of a charged particle beam in accordance with a position of the stage, and developing the substrate on which the pattern is drawn.
Further objects, features and advantages of the present invention will become apparent from the following detailed description of the embodiments of the present invention with reference to the accompanying drawings.